Printing telegraph



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UNITED STATES PATENT oi-rlcs Application October 27, 1932. Salt! No. 839,793

22 Olaiml. (Cl. 178-28) This invention relates to printing telegraphs nism in operating position and preventing other and pertains more especially to an improved and key manipulation until the printing function remorerapid printing apparatus for the transmissulting from the operated key has been comsion of news or messages and for intercommunipleted, thus positively P v nting the overiappins 6 cation between stations or ofllces. of two printinS Operations ycles.

One important feature of the invention resides These and other features of the invention will in a novel type wheel arrangement whereby the be st understood and appreciated rom the folprinting action is greatly facilitated and the speed lowing description of e d e t o of operation considerably increased. This feaselected 1 9 p rp s of illustration and shown in ture embodies the. use of two relatively adjacent e a pa ying drawings. in which type wheels on h h t required type chamm Fig. 1 is a front elevation of an embodiment tors are divided and arranged in the most eflicient Of my i v order. The wheels are normally in axial align- 2 iS e c ional View th ret roush tflhen ment and are so mounted that (1) they may be On line 0f 8- rotated to bring the desired type into printing Fi 3 is a pla Vi Of the yp Wheels and their position, (2) may be shifted axially to bring either Supporting carriage; wheel into alignment with a printing position B- 4 is e O t el va o partially in normally located between the wheels, and (3) the section; wheel thus aligngd may be moved laterally t Fig. 5 is a sectional view taken on line 5-5 of 20 impress its positioned type upon a platen. Co 4 and wi n Of the Wheels in Printing operating with these parts is other mechanism position against the p for causing the rotation and shifting of the type 3 is a View taken on line 6-6 of Fig. 4 wheels to print the selected characters upon a and ShOWinE the carriage in nd elevation; sheet on the platen and the construction and 8- 7 is e rightehend end section of the ma arrangement thereof is such that the operations chine taken on line 0f 8'- B0 are performed with great speed and facility. The 8 is 8- fr y onal view taken provision of such a mechanism comprises the pri- On line of mary object of my invention, Fig. 9 is a plan view of the unison mechanism Another important feature of my invention is taken 01111118 01 0 a novel mechanism for feeding the type wheel 8- 10 is e detail View taken on line 10-10 of carriage along the platen in the printing operation and for returning the same to its starting 11 is e fragmentary elevation of the p position. This mechanism embodies the use of a Wheel in s pement; 7 spring normally acting to return the carriage to 12 is a sectional w threugh the earstarting position, and power-operated means v g c utch taken on line 12-12 of tending continuously and non-positively to move the carriage forwardly. the forward movement of g.13 is a sectional view taken on line 13-13 the carriage being automatically controlled in a f Fi 7 manner quickly and accurately positioning the 14 8 8- W taken app xim ly on line carriage for printing, and the return movement 14-14 of Fig. 1 and showing a portion of the being accomplished by releasing the pulling action left-hand end of the machine in elevation; of the power-operated means and being con- Fi 15 is a sectional view taken on line 15-15 trolled by a power-driven member. The proviof Fig. 1; sion of a printing apparatus embodying this novel Fig. 16 is a fragmentary plan view of a switch mechanism comprises a further object of the 111- shown at the left-hand end of Fig. 1; vention. Fig. 1'? is a sectional view through the car- Among other objects of the invention is the rinse-returning mechanism taken on line 1717 provision of a novelelectro-magnetieally conof Fig. 1; trolled escapement mechanism for controlling the Fig. 18 is a sectional view taken on line 18-18 0 rotation of the type wheels, a novel mechanism of Fig. 17;

for bringing all the machines in the circuit to Fig. 19 is a right-hand end elevation of Fig. rest with the type wheels in a predetermined po- 17; and sition when the transmitting operations have Fig. 20 .is a diagrammatic view particularly been completed, and a simplified means for holdshowing the wiring circuits. no

ing any operated key of the transmitting mecha- The receiving and printing mechanism em.

bodying my invention'is illustrated in the drawings as having a transmitting keyboard and its cooperating mechanism combined therewith, al-

though it will be understood that, if desired. the transmitting mechanism-may be' eliminated and the apparatus used solely for receiving and printing. The use of the combined receiving and sending mechanisms, however, provide for twoting portions of the apparatus which cooperate with the keyboard are mounted on a plate 5 secured to the base '1 by screws 6. In the wiring diagram of Fig. 20, the transmitting mechanism is illustrated at the bottom portion of the sheet and the receiving and printing mechanism at the riage elements are symmetrical and will, therefore, be designated by like, reference characters, those on the left side being primed.

A fixed shaft 13 supported. intermediate its ends on the rear portion of the carriage has rigidly secured to each end thereof a U-shaped.

member 14. Threaded into the outer end of each such member and rigid therewith is an inwardly-extending stud 15. Slidably mounted on each stud is a sleeve 16 and fixed on each sleeve are a pinion 17 and a type wheel 18. A spring normally holds the, wheels somewhat spaced apart, as shown;

The two type wheels are rotatably positioned for printing by gears 20 splined to a shaft 21 extending along the track, the gears being in mesh with the pinions 17. The type wheels are also positioned axially for each printing operation and the selected wheel is then given a quick lateral movement to contact the positioned type character thereon with the platen 22. These axial and lateral movements are performed by two banks of electro-magnets 23 and 23' carried by and within the housing 8, the two banks of magnets being coextensive with the path of movement of the carriage and being adapted to operate the two type wheels respectively. Pivoted to the under side of the carriage 12 are two members 24, each member having one end 25 serving as anarmature for its bank of electromagnets and two other end portions 26 and 27. The ends 26 extend to a position respectively overlying two arms 28 of levers 29 pivoted to the carriage at 30. The other arm of each such lever has a forked end engaging over its corresponding sleeve 16 outside of the pinion 17 thereon. The arms 28 are normally held in raised position by a spring-pressed plunger 31 therebeneath. A bar 32 so connects the levers 29 together that they operate in unison. Each end portion 27 extends rearwardly of the carriage to a position beneath an adjusting screw 33 threaded into a portion 34 of its corresponding member 14. The arrangement is such that the energizing of one bank of electro-magnets will position one of the type wheels axially and cause it to be kicked laterally to contact with the platen, while energizing of the other bank of magnets will operate the other type wheel in like manner. It should be particularly noted that each armature 25 extends over and is adapted to be operated by a plurality of the electromagnets simultaneously.

The above-described mechanism is adapted to move one or the other of the type wheels axially inward to a printing positionnormally located between the two wheels, the spring 19 serving as a cushion between the 'wheels during this operation. Cooperatingwith V-shaped teeth 35 on the rear face of each pinion 17 is a V-shaped stop or anvil 4 on' the corresponding member 14. This anvil serves three functions, namely 1) centers the typewheel for printing when the teeth 35 are brought into contact therewith, 2) locks the wheel during the printing operation, and (3.) acts as a stop to limit the axial inward movement of the wheel to proper aligning position for printing. The members 14 and their type wheels are normally held in retracted position against stops 36 by springs 37, and a spring 38 serves to press an inking roller 39 lightly against the wheels.

- The shaft 21 is supported inuprights 40, whichalso support .the platen; 22, as hereinafter described. This shaft is driven from the motor 7 as follows. A worm 41 on the motor shaftmeshes with a worm gear v42 on a shaft 43, having a gear 44 thereon in mesh with a gear 45 on a shaft 46.

A gear 47 on the shaft 46 is frictionally connected thereto through a spring-pressed frictional clutch 48 and this gear 47 is in mesh with a pinion 49 on the shaft 21. normally held from rotation by means of an escapement mechanism at the opposite end of the shaft (Fig. 11). This mechanism comprises an escapement wheel 50 and a cooperating pallet 51. The pallet comprises two toothed'uprights mounted on a bar 52 disposed over and serving as the armature to three electro -magnets 53, the armature being pivoted over the intermediate magnet.

Each type wheel carries twenty characters on its periphery, the characters on'one wheel being directly opposite to those on theother wheel (Fig. 3) and the escapement wheel 50 has ten teeth corresponding therewith. Each movement of the pallet permits the type wheels torotate the extent of one character. These movements are controlled from the transmitting mechanism for the purpose of bringing the selected character's into printing position, as hereinafter described, it being understood that the use of two type wheels and the cooperating mechanisms for printing from either serves to divide the required characters into two groups and thereby greatly facilitate and speed up the printing operations.

The platen 22 is carried by a pair of arms 54 hung fromstuds 55 and adjustable into proper position by set screws 56. The paper sheet 57 extends from a supply roll 58 over the platen and-between two pairs of feed rollers 59. The two lower rollers are mounted on a shaft 60 and the two upper rollers are idlers mounted on arms 66. The feeding of the sheet is performed from The shaft 21 is the shaft 43 through a gear 62 thereon and 0011- means nected thereto through a friction clutch 63, the gear. 62 being in mesh with a gear 64 on the shaft 60. The shaft 60 is normally held from rotation by a pawl 65 engaging a ratchetwheel 66 on the shaft. This pawl is carried by an armature 67 cooperating with a pair of electro-magnets '68. When the electro-magnets are energized. the pawl is withdrawn and the sheet thus permitted to rotate the distance between two adjacent teeth on the ratchet wheel, this distance corresponding to the space of one type line on the sheet.

Carriage moving and returning mechanism The type wheel carriage 12 is normally returned to its starting position (extreme left, Fig. 1) by a spring-actuated wheel '10 fixed to a shaft '71 and connected by a steel band '12 to the carriage, a spring 73 normally turning the wheel in the carriage-retracting direction. This spring has its outerend 74 connected to the frame and its inner end mounted on and secured to a hub 75 fixed to the shaft. The carriage is moved forwardly against the action of the spring by power-driven means acting through a second wheel '16 having a steel band 77 thereon connected to the forward end of the carriage. This wheel is driven from the motor I as follows. The worm 41 on the motor shaft is in mesh with a worm wheel 78 on a shaft '19. A pair of bevel gears 80 connects the opposite end of this shaft with a shaft 81 on which the wheel "I6 is mounted.

The wheel 76 is mounted on a sleeve 82 loose on the shaft 81 and is held between two friction members backed up by a flange 83 on the sleeve and by a disk 84. A spring 85 and flanged member 86 serve to hold the wheel compressed between the friction members, the member 86, spring 85 and disk 84 being non-rotatably secured to the sleeve 82. An arm 104 on the base, resting light-' ly against the wheel '76, serves to limit axial movement of the sleeve 82- outwardly. Pinned to the shaft at the opposite side of the flange 83 is a sleeve 87, on a flange of which are carried a plurality of electro-magnets 68 so arranged that the fiange 83 serves as an armature therefor. Electric current is provided to the magnets from a pair of brushes 89. The shaft 81 is rotated in a direction to wind the band 77 onto the wheel 76, and when the magnets are energized this mechanism tends continuously and non-positively to move the carriage in the forward direction against the action of the spring and with a force sufllcient to overcome the spring.

Forward movement of the carriage under the action of the wheel '76 and its driving mechanism is prevented by a pivoted pawl 90 having one toothed end engaging a ratchet wheel 91 loose on the shaft 71, the other end of the pawl carrying an armature 92 located over a pair of electromagnets 93. A spring 94 normally holds the pawl engaged with the ratchet wheel. A collar 95, secured to the shaft '11, has a tooth 96 loosely engaging within a hole in the ratchet wheel and a relatively light spring 97 serves to rotate the ratchet wheel relative to the collar and shaft when the pawl is withdrawn. The arrangement is such that a current pulsation through the electro-magnets momentarlly'withdraws the pawl, whereupon the spring 97 quickly rotates the relatively light ratchet wheel a distance permitting reengagement of the pawl with the next adjacent tooth. It will be understood that the carriage and its connected parts move much more slowly and, therefore,

follow the ratchet wheel movement above dc-' magnets 99. This carriage-retuming movement would normally be so sudden as to cause, serious shock, and in order to prevent any such damaging action I provide the following novel controlling mechanism. A spring pawl 100 on the hub 75 is engaged with ratchet teeth on one end of a sleeve 101 loose on the shaft 71. Gear teeth 102 on the other end of this sleeve are in mesh with teeth 103 on the face of gear "(8 and the sleeve is thereby driven from the motor in a direction toratchet past the pawl (Fig. 18). The carriage can, therefore, return under the action of the spring '13 only at a speed permitted by the motor and corresponding to the speed of the motor-driven sleeve 101. Thus the carriage is always returned at a uniform and most eflicient speed and without danger of i iury.

When the sending operations have been completed, it is desirable that the machines be stopped and also necessary that they be brought to rest with the type wheels always in a definite and corresponding position. I have herein combined a single mechanism (Figs. 9 and 10) for performing these two functions. A worm 106 on the end of shaft 21 is adapted to receive between its thread convolutions a pin 107 carried in one end of a lever 108. This lever is pivoted at 109 and its other end cooperates with two normally closed switches 110, which switches, when opened, serve to break the main circuits to the machine. The arrangement is such that this breaking of the circuits takes place, and the shaft 21 thereupon stops, when the pin has reached the stop indicated at in Fig. 9. As thus stopped, the shaft 21 and the type wheels occupy a definite and predetermined position, which position is important when again restarting the machine. This position in the machine illustrated is such that the 8: character and the blank opposite thereto .on the type wheels are facing the platen. The machines will remain at rest until these switches are again allowed to close.

The lever 108 is also pivoted at 111 on an axis right angular to the pivot 109 and a rear portion 112 of the lever extends over and serves as an armature to a pair of electro-magnets 113. When these magnets are energized, the pivoting of the lever withdraws the pin, whereupon a spring 114 pivots the lever about 109 and permits the switches to close.

Transmitting mechanism The transmitting mechanism includes a member 120 supported on the plate 5 and having a circular series of outer contact segments 121 (Fig. 20) and a corresponding series of inner segments 122. A shaft 123 extends outwardly through the member 120 and carries brushes 124 and 125 respectively contacting with the segment series 121 and 122. Each series has twenty segments, which number corresponds with the twenty type characters on each type wheel. The shaft 123 is frictionally driven from the motor '7 as follows. A gear 126 on the shaft 46, and frictionally connected thereto by a friction clutch 127, is in mesh with a pinion 128 on the shaft 123. The shaft 123 may be stopped and held in a desired printing position by a pivoted pawl 129 engaging a toothed ratchet wheel 130 on.

the shaft. The position of the pawl is controlled by two electro-magnets 131--132 and 133. Energizing only the outer portion 131 of the first magnet attracts the pawl and withdraws it from the ratchet wheel, thus permitting the shaft to rotate, while energizing of the inner portion 132 of this magnet and also the magnet 133 serves to neutralize the first magnet and draw the pawl into clutching engagement with the ratchet wheel. It will be noted that the circuit from the outer brush 124 passes through the coils 132 and 133.

The keyboard portion of the transmitting mechanism includes a plurality of keys 136 pivoted on a shaft 137, a starting key 138, a space key 139 and a yoke 140 pivoted on a shaft 141. These keys are all provided with switches which are closed when the corresponding keys are depressed. A key 136 is provided for each character on the type wheels and one side of its switch is connected to a corresponding segment 121, and, since each such segment corresponds to two oppositely-disposed type characters on the two type wheels, the switches of two keys 136 are connected to each segment 121. For example,

the character &" on one wheel is opposite a 121 by a wire 144. The remaining key switches corresponding to the other type wheel characters are connected to the other segments 121 in like manner. One side of the starting key switch is also connected to the wire 144 for the reason hereinafterexplained. A switch 145 is closed when the yoke 140 is depressed and, since all the keys extend over the yoke, the yoke is depressed and its switch closed whenever any key is depressed. The yoke is also provided with a stop key 146 whereby it may be depressed and its switch 145 closed.

When the machines are in operation, the depressing of any key 136 causes the type wheels to rotate to a printing position corresponding with the depressed key, as hereinafter described, and thereafter to move the selected wheel axially into printing alignment and kick its positioned character into printing contact with the paper on the platen. It is necessary that the depressed key switches shall remain closed and the remaining keys prevented from operating during this cycle and I have provided the following means for this purpose. Each key bar carries a downwardly-extending plate 148 having a shoulder 149 thereon. A bar 150, supported on arms 151 pivoted at 152, extends along the key bars and is adapted to cooperate with the plates 148. A spring 153 normally holds the bar in its retracted position, wherein it does not interfere with the operation of the keys. On one end of the pivotal shaft 152 is an arm 154 which serves as an armature to an electro-magnet 155. When this magnet is energized, the bar 150 is pivoted forwardly to engage over the shoulder 149 of the depressed key and thereby hold it depressed, and to engage beneath the plates 148 of the remaining keys and thereby prevent their operation. The bar 150 remains in this position until the switch 145, which controls the electro-magnet 155. is opened or the electro-magnet short circuited.

The purpose of the inner segments 122 is to energize the escapement wheel magnets 53 and cause the shaft 21 and the type wheels to be rotated synchronously with the shaft 123 and thereby rotatably locate the type wheels in accordance with the character keys depressed. The intermediate magnet at 53 is connected to the ground tap 160 (Fig. 20) and current passes therefrom through one or the other of the two outside magnets in accordance with the position of a switch 161 controlled by a spring 162 and an electro-magnet 163, the opening and closing of this switch causing the escapement to operate and the shaft 21 to rotate, as will be understood. A wire 164 is in contact with alternate segments 122 and this wire is connected to the positive tap 165 through one of the switches 110. A circuit- 166 from the brush 126 extends through the tap 167, thence through the electro-magnet 163 through the tap 168, and from thence outwardly at T. L. to one or more like machines operated in synchronism with the machine illustrated. I term this T. L. circuit the type line since it controls the rotating of the type wheels. As the shaft 123 rotates, the alternately connected segments 122 serve to energize the magnet 163 intermittently and thereby cause the switch 161 to be alternately engaged with its two contacts, thus causing the escapement to function and the type wheels to rotate synchronously with the rotation of the segments and their shaft 123. This rotation continues until the segment 121 corresponding to the key depressed comes into contact with the brush 124, whereupon a current passes through the coils 132 and 133 and causes the pawl 129 to come into clutching engagement with the ratchet wheel 130. The shaft 123 and type wheels are thereupon arrested and the printing cycle takes place.

The following means serves automatically to select and print from the type wheel on which is the character corresponding to the key depressed. Considering the 8; and space" keys (Fig. 20) for example and the corresponding 8: character and blank which are opposite each other on the type wheels (Fig. 3), the upper terminals of the switches 142 and 143 are connected by the wire 144 to the same segment 121, which segment corresponds with the said 8: and blank located on the type Wheels. The lower terminals of these switches pass respectively through electro-magnets 1'75 and 176. The energizing of magnet 1'75 is adapted to close a switch 1'77 which, due to a resistance 1'78 in the line, sends a relatively weak current through the wire 179, while the energizing of magnet 1'76 is adapted to close a switch 180 and send a relatively strong current through the wire 179. These currents pass respectively through electro-magnets 181 and 182, adapted respectively to close switches 183 and 184 and thereby short circuit the current through the magnets 155, whereby to release the key holddown bar 150.

The wire 179 is connected to the tap 185 and the circuit passes from thence through two electro-magnets 186 and 187, through one of the switches 110 to the tap 188 and out on the P. L. line to one or more like machines operated in synchronism with the machine illustrated. 1 term this P. L. circuit the press line, since it controls the selection and operation of the type wheels. The magnet 186 controls the closing of a normally open switch 190 and the magnet 187 controls the operation of a switch 191 which is normally in position establishing a circuit through the bank 23 of press magnets, the movcurrent is adapted to close both switches against the action of their springs. Thus, if the &" key is depressed, a circuit is established through the press magnets 23, which thereupon operate to move the type wheel 18' and print the 8:" thereof on the platen. The remaining keys are connected in like manner whereby, upon the depress ing of a key, a circuit is established through the corresponding press magnets 23 or 23'.

When it is desired to return the carriage to its starting position, a carriage return" key is depressed, which key corresponds to the blank on the type wheel 18 opposite the character 6" on the type wheel 18'. when the type wheels and shaft 21 are brought to this position, a tooth 192 on the shaft 21 (Fig. 20) is in position against an arm 193 closing a normally open switch 194. A circuit is thereby established through the electro-magnets 68 and 69. The former serves to withdraw the pawl and permit the paper to feed the space of one line. The latter throws the switch 98 in a manner breaking the circuit through the magnetic clutch 88 and permitting the carriage to return under the action of the spring'73. The said latter also closes a switch at 195, which establishes a circuit through the carriage .release magnets 93, which thereupon function to hold the pawl 90 out and leave the ratchet wheel 91 freely rotatable during the carriage return.

As the carriage reaches its starting position, a lug 200 on the wheel engages against a rearwardly-extending portion 201 of the switch 98 and throws the switch back to the position shown in Fig. 20, in which position the circuit through the magnetic clutch 88 is reestablished and the circuit through the magnets 93 is broken. Simultaneously with this operation, a pin 202 on the wheel 70 engages and closes a switch 203 which short circuits themagnets 99. The purpose of this switch 203 is to prevent the magnets 99 from again throwing the switch 98 before the tooth 192 has permitted the switch 194 to open. The pin 202 serves to hold the switch 203 closed until the shaft 21 has rotated sufliciently to free the arm 193.

Operation other like machines being connected in the T. L.

and P. L. circuits and operating simultaneously with and in like manner to the machine illustrated. The machines are set into operation by depressing the starter key 138 of the local machine, which thereupon closes its two switches 205 and 206 and also depresses the yoke 140 and closes its switch 145.

The closing of the switch 205 establishes the following circuits through the local machine: (1) a circuit through the motor 7 along a wire 208; (2) a circuit 210, switch 145, coil 131 and magnets 155. The motor thereupon rotates, the pawl 129 is withdrawn, and the bar 150 is moved to key-locking position.

The brushes 124,and 125 are permitted to rotate until the brush 124 engages the segment 121,

to which the wire 144 is connected and which segment corresponds to the space opposite the 81" character on the type wheel 18. The following circuit is then established: switch 205, wire 210, switch 145, magnets 133, coil 132, brush 124, segment, wire 144, switch 206, wire 212, magnets 176, wire 214. This circuit closes the pawl 129 and stops the shaft 123 in the position illustrated in Fig. '20, which position corresponds to the initial and rest position of the type wheels. The circuit also closes the relay switch 180, which thereupon performs the following functions.

(1) Sends a strong current through the relay magnets 186 and 187 as follows: wires 210 and a 215, switch 180, coils 182, wire 179, tap 185, wire 216, magnets 186 and 187, wire 217, starting relay 218, tap 188, and out to the other machines on the P. L. line. The P.'L. line thereupon acts to energize the starting relays 218 of all the connected machines and cause their switches 219 to close, also to energize the coils 186 and 187 of all the machines and close their switches 190 and 191.

The closing of the starting switches 219 of the machines in the circuit has established the following circuits: 1) tap 165, switch 219, wire 220, motor 7, ground tap 160; -(2) wire 221, switch 98,

wire 225, magnetic clutch 88, ground 160; (3)- wire 226, switches 190 and 191, wire .227, press magnets 23, switch 228, wire 229, carriage release coils 93, coils 113, ground 160; (4) wire 230, switch 161, escapement coils 53, ground 160.

The current pulsation through above circuit (8) causes the press magnets 23 to move the type wheel 18 axially into printing alignment and then to kick it toward the platen, no printing taking place, however, since the character location in printing position thereon is blank; causes the magnets 93 to release the pawl and permit the carriage to feed forwardly one space; and causes the magnets 113 to withdraw the pin 107 and permit the switches to close. The closing of these switches short circuits the relays 218, whereupon their switches 219 open.

The operations above described immediately follow the closing of the relay switch 180 and the closing of this switch also energizes the coil 182 and closes its switch 184. The closing of the switch 184 short circuits the coils 155, whereupon the key hold-down bar 150 is released, the starting key returns and switches 205, 206 and 145 open.

The motors of all the machines are now running and the printing operations await only the depressing of the keys of the characters to be transmitted, it being understood that all the type wheels are in position corresponding to the position of the brush 124, this position being such that the character 81" on the type wheel faces the platen. If the 8: key is now depressed, the type wheels will not be rotated but the machines will function in place immediately to print the 8; character." If the key "B" 'is depressed, a switch like the switch 142 is closed, as is alsothe yoke switch 145. The closing of switch 145 causes a current to pass through coils 131 and 155, whereby to withdraw the pawl 129 and engage the key hold-down bar 150. The shaft 123 thereupon rotates until the segment 121, corresponding to the 13 character on the type wheel, contacts with the brush 124, and during which time the contacts 122. are acting through the switches 161, escapements 53 and over the T. L. line to rotate the type wheels of all connected machines synchronously with the shaft 123. Contacting of the brush 124 with said segment establishes a circuit through the coils 132 and 133, whereupon to engage the pawl 129 and stop the shaft 123. This same circuit energizes the coils'175 which closes the switch 177, thus sending a relatively weak current through coils 181, 186, 187, and out on the P. L. line to the other machines.- This relatively weak pulsation closes the switch 190 but not the switch 191. The following circuit is thereby established: wire 226, switches 190 and 191, press magnets 23', coils 93, coils 113. The press magnets thereupon function to align axially the type wheel 18' and kick the positioned character B" thereon against the platen. The energizing of the coils 93 permits the magnetic clutch 88 to move the carriage one space forwardly. The energizing of the coils 181 closes the switch 183 and short circuits the key hold-down magnets 155, each key thereby being automatically held down only long enough to complete the printing operation.

When the transmitting operations have been completed, it is desirable that allthe machines be brought to rest, which function is performed by depressing the stop key 146. The switch 145 is thereby closed, which causes the pawl 129 to be withdrawn and the key hold-down bar 150 to be closed. The shaft 123 thereupon rotates and, through the escapement 53, causes all the type wheels to rotate synchronously therewith. This rotation continues until the pin 107 engages the stop 105 (Fig. 9), at which position the switches 110 are opened by the arm 108 and the machines all come to rest with the type wheels so located that the 8: character and the blank opposite thereto are facing the platen.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

' 1. In a printing apparatus, a platen, two relatively adjacent type wheels, means including a carriage movable along the platen and support ing the wheels for rotary movement whereby the type thereon may be brought selectively into printing position, means for shifting the wheels axially to bring one or the other of the wheels selectively into printing alignment, and means including two fixed stops on the carriage and cooperating teeth fixed relative to the two wheels respectively for rotatably locating the wheels in printing position when moved axially and holding them in that position during the printing operation.

2. In a printing apparatus, a platen, a shaft parallel with the platen, a carriage movable along the shaft, two relatively adjacent type wheels rotatable in the carriage on axes parallel to the shaft, means connecting the wheels for rotary movement from the shaft whereby the type on the wheels may be brought selectively into printing position, means for shiftingthe wheels axially to bring one of the wheels selectively into printing alignment, and meansfor thereafter moving the selected wheel laterally against the platen to perform the printing operation.

3. In a printing apparatus, two relatively adjacent type'wheels, means supporting the wheels for rotary movement whereby the type thereon may be brought selectively into printing position, said means supporting the wheels for independent relative movement laterally, resilient means normally holding the wheels substantally in axial alignment, means for shifting both wheels axially in two directions to bring one or the other of the wheels into printing alignment, and means for thereafter moving the selected wheel laterally to perform the printing operation.

4. In a printing apparatus, a platen, a shaft parallel with the platen, a carriage movable along the shaft, two relatively adjacent type wheels carried by the carriage adjacent to the platen, connections from the shaft to the wheels whereby to rotate the wheels and bring the type thereon into printing position, and means for shifting the wheels axially to bring one of the wheels selectively into printing alignment,

5. In a printing apparatus, means providing a track, a carriage mounted on and movable along the track, a shaft extending along and parallel with the track, two relatively spaced and normally coaxial type wheels mounted in the carriage, connections from the shaft to the wheels whereby to rotate the wheels together and bring the type thereon into printing position, and means for shifting the wheels axially in opposite directions whereby to bring one or the other of the wheels into alignment with a printing position normally located between the wheels, each wheel having a type location on its periphery opposite to a like type location on the other wheel.

6. In a printing apparatus, a platen, two relatively adjacent type wheels adjacent thereto, means supporting the wheels for rotary movement, axial movement and relatively independent lateral movement, a power actuated member, means operated thereby and acting directly on one of the wheels for shifting the same axially in one direction to bring such wheel into alignment with a printing position normally located between the wheels, and other means also operated by said member for thereafter moving the said wheel into printing contact with the platen.

7. The combination of' claim 6, in which an actuating means is provided for each wheel and includes a single actuating element the movement of. which first causes the axial shifting of its wheel into printing position and directly there after moves the wheel laterally into printing contact with the platen.

8. In a printing apparatus, a platen, a carriage adjacent to and movable along the platen, two relatively adjacent type wheels, two normally coaxial and independent shafts rotatably supporting the wheels on the carriage, cooperating means permitting axial movement of the wheels and relatively independent lateral movement of the shafts and their wheels, means for rotating the wheels to bring the type thereon into printing position, and actuating means for shifting both Wheels together axially in one direction or the other to bring the selected wheel into alignment with a. printing position normally located between the wheels and thereafter moving the selected wheel into printing contact with the platen.

9. In a printing apparatus, a platen, a carriage movable along the platen, a shaft extending along and parallel with the platen, two relatively adjacent type wheels, means supporting the wheels for rotary movement, axial movement and relaafter moving the selected wheel into printing contact with the platen.

10. The combination of claim 9, wherein the said power-actuating means are two banks of electro-magnets and the last-named means include armatures respectively cooperating therewith.

11. In a printing apparatus, a platen, a carriage movable along the platen, a type wheel carried by the carriage adjacent to the platen, means for rotating the wheel to bring the type thereon into printing position, a bank of electro-magnets extending along the path of carriage movement, and means including an armature carried by the carriage and adapted to be operated upon by said bank in any position of the carriage along the platen to move the wheel into printing contact with the platen.

12. The combination of claim 11, in which said armature is of a dimension extending over and actuated by a plurality of said magnets simultaneously.

13. In a printing apparatus, a platen, a type carriage movable therealong, resilient means connected to the carriage and acting thereon to return the same to starting position, poweroperated means tending continuously'and nonpositively to move the carriage in the forward direction against the action of the spring and with a force suflicient to overcome the spring, means normally preventing such forward movement, and cooperating means permitting the carriage to move forward one type space at each printing operation.

14. In a printing apparatus, a platen, a type carriage movable therealong, resilient means connected to the carriage and acting thereon to return the same to starting position, means including power-driven electro-magnetically-operating elements tending to move the carriage in the forward direction against the action of the spring and with a force sufiicient to overcome the spring, means normally preventing such forward movement, and cooperating means permitting the carriage to move forward one type space at each printing operation.

15. The combination of claim 13 plus means for releasing the said force and thereby permitting the spring to return the carriage to its starting position.

16. The combination of claim 14 plus a keyoperated switch for breaking the electric circuit to said elements and thereby permitting the spring to return the carriage to its starting position.

17. The combination of claim 13 plus means for releasing the said force and thereby permitting the spring to return the carriage to its starting position, and means including a motor-driven element cooperating with the carriage and limiting its return movement to a speed corresponding with that of the element.

18. In a printing apparatus, a type wheel having a plurality of characters thereon, a motor frictionally connected to rotate the wheel, an

escapement including two electro-magnets so controlling the rotation of the wheel that the characters thereon are brought consecutively into printing position synchronously with the making of circuits alternately through said magnets, and means for alternately breaking the circuit through one of said magnets and making the circuit through the other magnet.

19. The combination of claim 18 plus means including an electro-magnetically controlled switch for performing the said making and breaking operations.

20. In a printing apparatus, a type wheel having a plurality of characters thereon, an electric motor for rotating the wheel, a switch to the motor, a member connected to and rotated synchronously with the wheel, means cooperating with the switch and engageable with the member to be moved thereby as the member rotates, said means being adapted to open the switch when the member and wheel have rotated a predetermined amount and to a predetermined position, and electro-magnetic means for withdrawing the first-named means from the member.

21. In a printing apparatus, transmitting means including a plurality of depressible keys having shoulders thereon, a type-carrying member, means ,for causing printing contact of the type of said member upon the depressing of said keys, a pivotally-mounted bar adapted in one pivotal position to engage said shoulders and hold the depressed keys in depressed position, an electromagnet acting to hold the bar in that position until the resulting printing action has taken place, and means including a switch for then automatically breaking the electric circuit through the magnet and thereby permit the bar to move to its other position.

22. In a printing apparatus, a type wheel having a plurality of characters thereon, a motor frictionally connected to rotate the wheel, an electro-magnetically controlled escapement for controlling the rotation of the wheel, two circular series of contact segments corresponding with the characters on the wheel, two brushes contacting respectively with the two series, motor driven means for causing a relative rotation of the brushes and segments, means including a circuit through one of said series and its brush for operating the escapement in synchronism with said rotation, transmitting means including a plurality of switches respectively connected to the segments of the other series, means providing a circuit through the said other series and including an electro-magnetically controlled member for stopping such rotation, said member acting to stop the rotation whenever its brush engages a segment whose connected switch is closed and being adapted to remain in position preventing said rotation until another one of said switches. is closed, and means for moving the member to position permitting further rotation when said another switch is closed.

' ANDREW T. MACCOY. 

